RDMA/counter: Fix num_counters leak on bind_qp failure in alloc_and_bind()

When __rdma_counter_bind_qp() fails in alloc_and_bind(), the error path
jumps to err_mode which frees the counter without decrementing
port_counter->num_counters. The only place that decrements is
rdma_counter_free(), which is unreachable since the counter was never
successfully bound.

This leak accumulates across repeated failures, permanently preventing
the port from switching to AUTO mode (-EBUSY in __counter_set_mode())
and blocking the MANUAL→NONE auto-revert in rdma_counter_free(). When
the mode was NONE before the call, the MANUAL mode set by
__counter_set_mode() also leaks since the revert logic is never
reached.

Add an err_bind label between the num_counters increment and the
existing err_mode label. It decrements num_counters and mirrors the
MANUAL→NONE revert from rdma_counter_free(), ensuring the port state
is fully restored on bind failure.

Link: https://patch.msgid.link/r/20260520104546.1776253-2-cuitao@kylinos.cn
Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

diff --git a/drivers/infiniband/core/counters.c b/drivers/infiniband/core/counters.c
index c3aa6d7fc66b6eb416d3f4c36644b1479bf2b9b1..5ddd607d5fbef4a19b22d9864f8cc91725879ee7 100644 (file)
--- a/drivers/infiniband/core/counters.c
+++ b/drivers/infiniband/core/counters.c
@@ -198,12 +198,20 @@ static struct rdma_counter *alloc_and_bind(struct ib_device *dev, u32 port,
 
        ret = __rdma_counter_bind_qp(counter, qp, port);
        if (ret)
-               goto err_mode;
+               goto err_bind;
 
        rdma_restrack_parent_name(&counter->res, &qp->res);
        rdma_restrack_add(&counter->res);
        return counter;
 
+err_bind:
+       mutex_lock(&port_counter->lock);
+       port_counter->num_counters--;
+       if (!port_counter->num_counters &&
+           port_counter->mode.mode == RDMA_COUNTER_MODE_MANUAL)
+               __counter_set_mode(port_counter, RDMA_COUNTER_MODE_NONE, 0,
+                                  false);
+       mutex_unlock(&port_counter->lock);
 err_mode:
        rdma_free_hw_stats_struct(counter->stats);
 err_stats: